The Science of Kissing: A Q&A with Sheril Kirshenbaum

The big day is finally here: Valentine’s. But after weeks (er, hours?) of planning, is the perfect V-Day smooch more science than passion?

On February 7, 2008, the writer Sheril Kirshenbaum posted a brief article called “The Science of Kissing” on a blog called The Intersection. Inspired by an article she’d read in Scientific American, Kirshenbaum wrote a few hundred words on why, exactly, people kiss. The post was a hit, and Kirshenbaum quickly realized the subject was worth more than a blog post — it would make a great book.

A little more than three years later, Kirshenbaum published The Science of Kissing: What Our Lips Are Telling Us, an investigation into osculation. The author spoke to the National Post’s Mark Medley on the phone from Austin, where she’s a research scientist in the engineering department at the University of Texas.

Q: This started off as a blog post, right? When did you realize it was worth expanding into a book?

A: It really surprised me, because it wasn’t a subject I expected to be writing about at all. Immediately after I wrote the blog post, I was getting so many e-mails and questions from people — it just never stopped. Then, a couple months later, the American Association for the Advancement of Science said ‘Co-organize this symposium on it for us, we think it’s a great topic.’ And the media coverage of that symposium — which was the following February, 2009 — was just so enormous, bigger than anything I think even they had seen before. So it just seemed like what a great way to bring people into the world of science. I think this gives people a real glimpse into what a laboratory is like, and how different inter-disciplinary fields can come together and tell a story. So I guess it was just after that symposium that I immediately said this is going to be a great book. And it hasn’t been done before!

Q: For something that is so ubiquitous, and something that most people do on a daily basis, the fact that a book hadn’t been written on this subject surprised me. Why do you think that is?

A: It’s really tricky to write about any sexually-charged topic, because there’s so many areas that it can be misinterpreted. Some people don’t take those subjects as seriously. And I think people are also a little daunted by approaching the kiss scientifically, because it can have so many meanings. So how do you talk about it? How do you really dissect its significance? Either it has too much significance or it’s just not serious enough for science.

Q: What’s interesting is that the kiss isn’t just scientific, but anthropological, and sociological — there’s all these different branches.

A: Right. I thought it was so neat that there are so many different researchers — endocrinologists, anthropologists, neuroscientists — who are considering aspects of both the kiss and other intimate behaviour. I really felt like having the scientists on board as I was composing the book added so much just to the avenues I was pursuing. I was so fortunate that everyone wanted to be on board and I didn’t have this pushback at all. It just became a lot of fun. I owe so much to them for participating and getting excited and helping me.

Q: What kind of misinformation to people have about kissing?

A: I just kept coming across this one sort of factoid, and it’s everywhere — it was even in some books — and it said a kiss contains 26 calories. And I just thought that’s absolutely ridiculous. But why is that everywhere? Where is it coming from? At the beginning of 2010, I was eating Hershey’s kisses, and I noticed on the bag that there was 26 calories. And I thought, ‘Okay, that’s how misinformation happens.’ Someone at some point said there’s 26 calories in a kiss, and then that got perpetuated. You know when you’re little and you play that game Telephone? Someone says something, and it gets moved and shifted — that’s the way a lot of science reporting seems to work. And so where the story starts and where you hear it are often in totally different places.

Q: A danger of kissing that I hadn’t really given much thought to is biting.

A: With the rise of vampires, yeah.

Q: Is that legitimate? I wasn’t sure if you were being tongue-in-cheek or not.

A: In some ways I was, but actually there’s a lot of teenagers who watched the Twilight saga, and they’re watching True Blood, and they think it’s really sexy, this idea of biting and sharing blood. There’s so much danger to exposing a lot of things that are just harmless in our saliva directly into our bloodstream. You can get blood poisoning. So much can happen to your body. So I think it’s worth warning people, especially teenagers, not to try it.

Q: Besides biting, what’s the oddest form of kissing you encountered.

A: One of my favourite things to do was read these explorers journals from the 1800s. There’s one particular culture — I don’t have the book in front of me — they didn’t kiss mouth to mouth, but they actually bit at each others eyelashes. That probably takes the cake.

Q: I don’t really understand how that works.

A: I’m not really sure. There’s this description — as both partners approached orgasm they would frantically nip at each others eyelashes.

Q: I think you compare that to what lion’s do when they mate.

A: There’s so many kissing-like behaviours in other species, but scientists have to be careful how they talk about kissing across the animal kingdom; we don’t want to [be] anthropomorphizing. We have to be very careful when we’re describing other animals’ emotions. But most behaviourists, at the same time, will say when you see birds nuzzling each other, and nipping at each other, they’re definitely mates, it’s definitely a way to express affection. So I think there’s a deep, instinctive basis for why we do it, and looking around the animal kingdom gives us some clues.

Q: Are there any modern cultures where kissing isn’t common?

A: That’s a very difficult question, because, as I said in the book, before the rise of the Internet, before we were travelling as much as we are, anthropologists, I think it was in the 70s, estimated that only 90% of people were kissing. In all likelihood that has only spread, and there are very few parts of the world where Western culture — you know, Hollywood films, all these things — don’t permeate and create this kind of cultural acceptance of mouth-to-mouth kissing behaviour. But in terms of what people do in public, there are still a lot of places where kissing is considering completely indecent; many parts of the Middle East, for example, and until recently parts of Japan and China people did not kiss in public. But now younger generations are starting to do that more and more.

Q: What happens to our bodies when we kiss?

A: It depends if it’s a good kiss or a not-so-good kiss. But if we’re talking about a good, passionate, the-chemistry-is-right-kind-of-kiss, we’re gathering so much information about the experience and the other person that’s really helping us decide if we should take things to the next level. So unlike when you’re just standing next to someone, getting to know them, talking, or perhaps dating over the Internet, when we’re kissing someone we’re in their personal space, and there’s so much we can gather — not just visually but in terms of scent, in terms of taste, in terms of touch — all of our senses are engaged and involved, and that is creating this cascade of signals to our brain which, particularly for women, really helps us understand if we’re compatible with the other person. When a kiss feels right, we’ll see a rise in a hormone known as the love hormone — Oxytocin. And Oxytocin is responsible for feelings of attachment, for social bonding, for maintaining long-term relationships, not just that immediate first kiss. There’s also usually a rise in Dopamine, particularly within first kisses in a relationship, and that spikes due to novelty, but also due to pleasurable experiences. It’s responsible for craving, for desire, for that can’t-wait-to-be-with-someone feeling we have when we think we’re falling in love. Serotonin is another one that’s a neurotransmitter that has to do with obsessive compulsive feelings, so that can’t eat, can’t sleep, can’t stop thinking about someone has a chemical basis in our bodies. As I was writing this book, what was becoming more and more apparent and just so interesting to me was, all of these feelings and things we describe when we’re really falling for someone, that is explained by all of these signals in our bodies moving around, and they influence what we do, and how we feel. But at the same time I didn’t want to say there’s no such thing as romance, because of course there’s that magical feeling in a first kiss.

Q: Why do we close our eyes when we kiss?

A: During novel experiences, and also during pleasurable experiences, our pupils dilate. Even when we look at someone we like, when someone is making eye contact with someone else, if they’re attracted to them their pupils will dilate. That’s also something that will happen during a good kiss. So, as a result, because more light would be getting in, we’re probably closing our eyes not just because it’s something you’re told — people close their eyes when they kiss — but it’s something that naturally happens.

Q: There’s a whole chapter on cooties; did this turn you off kissing?

A: No, because in the end there are more dangerous germs transmitted during a handshake than during a kiss. As long as bacteria and viruses aren’t getting into our bloodstream, for the most part, I think kissing is really good for us when you weight the pros and the cons. It didn’t ruin the experience for me, but it’s definitely something that seems to disturb many people that I’ve spoken to.

Q: Looking at your research, kissing as we know it now has only been around for five or six thousand years, if you look at the written record. What’s the future?

A: The earliest literary evidence we have of kissing dates back about 3500 years, but considering there’s so many similar behaviours in the animal kingdom, especially with primates — I have video of bonobos kissing for 12 minutes, just sucking on each others tongues — I suspect that humans have probably been meeting at the mouth for as long as we’ve been around,we just don’t have that in any sort of historical record. On and off, of course. There’s places that thought that the behaviour was disgusting. We weren’t using Listerine, mouthwash or toothbrushes for very long, so I’m sure it was a very different experience for quite a while. But if we’re talking what’s coming down the line, our relationships are changing. The dating landscape is changing. Virtual technologies are changing. And people really like to kiss, so I think it’s very possible, as robotics improve, as even as the sex toy industry improves, kissing will continue to be more popular than ever, and people will probably be finding new means to have that experience. Especially women, because men seem to see it more as a means to an ends.

Q: As you say when discussing that one robot, Roxxxy, the manufacturer says its not really meant for kissing…

A: No, the lack of a kissing function doesn’t seem to be an impediment for Roxxxy’s users.

Q: So after spending a couple of years researching this, has any of the mystery vanish from kissing?

A: No, actually I’d say quite the opposite. I’m consciously aware of doing it more, and I recognize how much it means in terms of maintaining that special connection. My husband and I are so busy, we’re in a million directions everyday, but I really value taking the time and just making sure we kiss each other goodbye in the morning. I guess by understanding the science behind what it promotes in our bodies and why it matters I think about it a little more.

• The Science of Kissing by Sheril Kirshenbaum is published by Grand Central Publishing [$22.50].